Microphone



(Model.)

0. 1). HASKINS.

MICROPHONE.

No. 266,286. Patented 001;. 24, 1882..

UNITED STATES ArnNr rate.

CHARLES D. HASKINS, on NEW YORK, N. Y., ASSIGNOR, BY MEsNn ASSIGN-MENTS, TO THE WESTERN ELECTRIC COMPANY, or CHICAGO, ILLINOIS.

MICROPHONE.

SPECIFICATION formingpart of Letters Patent No. 266,286, dated October24, 1882, Application filed July 8, 18 81. (ModeL) Figure l isafull-sized perspective of a microphone embodying my improvements' Fig. 2is an eicvation of certain portions thereof on a scale double that ofFig. 1. Fig. 3 is a plan showing the connections in detail. Fig. 4 isaperspective of a metallic spring carrying a screw or point. The screwmay be provided with a cylindrical head, as shown, in which may beprovided one or more holes. By inserting a leverin one of the holes thescrew may be adjusted.

The same parts are indicated by similar letters of reference in thedilferent figures of the drawings.

A is the mouth-piece. B is the inductioncoil, and O the battery in thelocal circuit. The diaphragm D is of the usual form. The stud (0supports the rubber disk b. Two carbon pieces, 0 c, are provided in thedisk. The pieces of carbon should be surrounded by metallic sheath (1 d,to which connecting-points e e for the local battery may be attached.

The points f, g, It, and i are adjusted to the carbon pieces by means ofsprings f, g, h, and 1', so that the pressure of points fg and h i willbe varied by the vibrations of the diaphragm. When the resistance atpointsfg is increased the resistance at points It i is diminished, andwhen the contacts are best atpoints fg the contacts are poorest atpoints h 1'. These screws, which terminate at points f g h i, areweighted with the cylindrical heads. Their inertia will therefore aidmaterially in efi'ecting the variation of contact of the electrodes.Suppose the contacts at points fg to be at their best. Thebattery-circuit may be 50 traced byline k to contact-point e and carbonc, thence by contact-point g and spring g to line Z, and thence throughthe inductioneoil, and thence by line m to the spring f, and thence bycontact-pointf to carbon 0 and 'contact-pointe, and thence by line a tothe pole of the battery. Suppose the better contact were at the pointshi. The battery would then find circuit from one pole by line 70 tocontactpoint e and carbon 0, and thence by contactpointor screw it andspring h to wire at through the primary coil, and by wire Z, spring i,and point t' to carbon 0, and thence by contactpoint e and wire a to itsother pole. The vibrations of the diaphragm thus cause thelocal circuitto be sent in undulatory reversals through the primary of theinduction-coil.

I claim- 1. The combination of the battery included in the circuitbetween the electrodes, branch connections, substantially as shown anddescribed, and the weighted electrodes supported entirely by thediaphragm, whereby the current of the battery may be sent in undulatoryreversals through that portion of the batterycircuit included betweenthe, said branch conneotions.

2. The combination oftwocarbon pieces with tour contact-points, twopoints foreach carbon piece, the diaphragm, primary of inductioncoil,and circuit connections, as described, whereby the currentot' thelocalbatteryissent in undulatory reversals, as and forthe purpose set forth.

8. The combination of battery (J in the circuit of line It a, the line 1m, including the primary of the induction-coil, the branch connections,main line, secondary of inductioncoil, electrodes, and diaphragm,whereby induced currents may be sent to line in undulatory reversals, asand for the purpose speci- 9o fled.

4. The combination of conducting-springs f 9 Mt", supporting thecontact-pointsfg It 1', respectively, provided with weighted heads, thecarbon pieces 0 c, the disk supported at 5 the center by the stud a, thediaphragm, and circuits, substantially as shown and described.

CHAS. D. HASKINS. Witnesses:

' WM. 1?. ILLENSWORTI-I,

O. K. DEUTSGH.

